Conventional stamped-steel wheels comprise a cylindrical wheel rim defining an inner wall and a substantially circular stamped wheel disc connected to the rim at an intermediate point of the rim's inner wall. The main characteristics of this type of conventional wheel are its low manufacturing cost and its attractive appearance. With the passing of time and the sophistication of the vehicle market, especially light-weight commercial and utility automobiles, the use of these conventional wheels has been reduced to low-cost vehicles or vehicles used in commercial applications where the use of wheels cast from light-metal alloys and having a more elaborate appearance and a much higher manufacture cost is not desirable or economically feasible.
To provide wheels that have a low manufacturing cost and an attractive appearance, wheels have been developed with a stamped disc having a diameter that is the maximum diameter of the wheel and fixed at the wheel rim's back surface. This style of wheel is much more attractive than conventional stamped wheels, and the manufacturing cost continues to be reduced so that wheels of this style have great potential in the consumer market.
In spite of having an attractive appearance, the question of centering the rim while fixing the rim to the disc presented difficulties. It is necessary to position the rim very carefully to fix it to the disc. Typically, the rim is fixed to the disc by welding in order to avoid manufacturing concentric wheels, which may cause uncontrollable vibrations when the vehicle moves if the wheels are off-center.
In order to facilitate centered fixation between the disc and the rim, a number of solutions have been proposed, generally constituted by concentric channels or recesses made in the disc by cutting tools. The free end of the rim is then positioned in the channels or recesses and welded. To make this preliminary fitting more precise, rims have been developed with the free end being specifically prepared by using a cutting tool.
In spite of achieving their objectives, these solutions result in additional manufacturing steps, incurring a higher production cost due to the need for additional machinery and personnel, wear of the cutting tools, material waste, and added time spent producing the wheel. Moreover, the larger the number of steps for manufacturing the wheel increases the chances of manufacturing flaws.
In this regard, U.S. Pat. No. 4,610,482 discloses a wheel provided with a rim associated with the upper surface of a disc. The upper surface of the disc is shaped in a mechanical shaping to remove material, forming a cavity in the region where the rim is associated. Additionally, in this wheel the free end of the rim also undergoes a similar shaping process by means of a cutting tool, which brings about a perfect fit between the disc and the rim. In addition, a surface is configured to serve as a stop for indicating a perfect fitting. As expected, this wheel has a considerably high manufacturing cost due to the large number of steps required for manufacturing the wheel.
Brazilian patent application P1 9916810, corresponding to PCT US99130165, discloses a wheel rim having a free end turned inward, defining a flange. The flange surface interfaces with the disc and is completely parallel to the corresponding disc surface to allow correct centering. Although less effective than the structure disclosed in the document discussed in the preceding paragraph, similar solutions may further be found in document US 2001/0038238.
Thus, there is a desire for a wheel that allows centering of the rim on the disc without requiring additional manufacturing steps.